JPH03319Y2 - - Google Patents

Description

[Detailed Description of the Invention] (Industrial Field of Application) The present invention relates to a powder press molding device, and more particularly to a powder press molding device for press molding a powder compact having an undercut portion.

(Prior Art) Generally, a technique is known in which a mold is filled with various metal powders, ceramic powders, or mixed powders thereof, and a powder compact is obtained by press molding.

By the way, in order to obtain a powder compact having an undercut-shaped part, for example, Japanese Patent Application Laid-Open No. 59-219401 discloses that a mold consisting of a die, a lower punch, and a core rod is filled with metal powder, and the upper punch is used to lightly punch the powder. After performing powder compression molding, the upper punch is raised and a spacer is attached to the part corresponding to the undercut shape, and the metal powder is further filled and compression molded integrally with the upper punch to form the desired molded product. A technique for manufacturing a sintered part is described in which the spacer is removed after molding and the sintered part is manufactured by sintering.

(Problems to be solved by the invention) According to the manufacturing technology for sintered parts with undercut shapes described in the above-mentioned publication, there is a process in which metal powder is first lightly pressurized, and then an upper punch is formed. There are many steps involved in manufacturing one molded object, such as the raising process, the process of attaching a spacer, the process of integral pressure molding, and the process of removing the spacer, and therefore a lot of time is spent on manufacturing. However, since the molded body is manufactured by two pressurizing processes: the first pressurizing process and the integrally pressurizing process, the molded body is a molded body that is integrally compression-molded at one time. Compared to this, it is difficult to obtain a uniform bonding force over the entire molded body, and when installing a spacer with a complicated shape to obtain a complicated undercut shape, the molding accuracy decreases due to fluctuations in the spacer position. There are issues such as what to do.

(Means for Solving the Problems) A powder press molding apparatus according to the present invention is a powder press molding apparatus that presses powder to produce a powder compact having an undercut portion on the side surface. A vertically movable split die is provided in the die portion to be formed, a side core is provided in the split die so as to be slidable in the horizontal direction, and the side core is set at a molding position where its inner end protrudes into the molding cavity and is retracted from the molding cavity. An actuator that is driven to a retracted position is provided, and an elastic support means is provided that elastically supports the divided die and allows the divided die to be lowered by the pressing force when pressing the powder filled in the molding cavity with a punch. It is something.

(Function) Since the powder press molding apparatus according to the present invention is configured as described above, the powder is applied to the lower part of the undercut part of the cavity while the side core provided in the split die is held in the retracted position. After filling, the side core is driven by an actuator to a molding position where the inner end protrudes into the molding cavity, and the remaining portion of the cavity is further filled with powder and pressed using an upper punch and a lower punch.

When pressing with an atsupa punch, the powder in the cavity contracts, but the pressing force during molding causes the dividing die and side core to move down against the elastic force of the elastic support means, so the undercut is prevented by the side core. part is formed.

(Effect of the invention) According to the powder press molding apparatus according to the invention, as explained above, the side core can be driven to the molding position and the retracted position by the actuator, so that the side core can be held at the retracted position. In this state, the portion of the cavity below the undercut portion is first filled with powder, and then the side core is projected to the molding position, and in that state, it is possible to fill the remaining portion of the cavity with powder. Therefore, it is possible to uniformly fill the entire cavity with powder, so that it is possible to produce a powder compact with excellent compaction density.

The split die with the side cores is movable up and down, is elastically supported by elastic support means, and can be lowered by the pressing force of the press, so it can cope with the shrinkage of powder in the cavity during molding. A cut portion can be formed reliably.

In addition, since the powder in the cavity can be press-molded in one step, a powder compact having an undercut portion can be manufactured without reducing productivity.

(Example) Hereinafter, an example of the present invention will be described based on the drawings.

In this embodiment, a powder press molding apparatus is used to form a powder compact 29 shown in FIG.
It is provided so as to be able to protrude freely, and its horizontal tip portion forms an undercut portion.

As shown in FIGS. 1 to 4, the powder press molding apparatus 1 includes a base 2, four columns 3 of appropriate length extending upward from the base 2, and a The fixed die 4, the lower punch 5, the air cylinder 6 that drives the lower punch 5 in the vertical direction, the four pillars 7 of appropriate length extending upward from the upper surface of the die 4, and the four pillars 7. It basically consists of an upper frame 8 fixed to the upper end, a hydraulic cylinder (not shown) that drives an upper punch 9 built into the upper frame 8, and an upper punch 9 attached to a ram 28 of the hydraulic cylinder. There is.

In order to clarify the following explanation, the X direction will be referred to as the left side and the Y direction will be referred to as the front side in the drawings.

The die 4 has a circular shape in plan view and is thick in the vertical direction, and has a square punch hole 10 vertically formed in the center thereof, into which the lower punch 5 is inserted.

Near the left periphery of the die 4 is a horizontal die 12.
Air cylinder 1 for driving (side core)
1 is provided in the left-right direction and is fixed to the upper surface of the die 4.

A mold mounting hole 14 for vertically movably mounting the horizontal mold 12 and the split die 13 is formed in the punch hole 10.
It is formed continuously with the punch hole 10 at a position adjacent to the left side of the punch hole 10 .

The mold mounting hole 14 has a depth extending from the upper end surface of the die 4 to the vicinity of the lower end, has a width in the left-right direction from the left end of the punch hole 10 to the same extent as the punch hole 10, and has a punch hole in the front-rear direction. It is formed somewhat longer than the length of one side of 10.

The split die 13 has a spring receiver 15 in the lower half of the middle stage and a spring receiver 1 in the upper half of the middle stage.
5 and a guide portion 16 formed to have a width approximately half of that of the guide portion 16.

A spring receiving groove 15a is formed on the lower surface of the spring receiving part 15 over the entire length in the front and rear direction, and a spring receiving groove 15a is formed in the lower surface of the spring receiving part 15.
A guide hole 17 through which the horizontal die 12 is inserted is formed horizontally in the left-right direction at the lower part of the guide hole 17 .

The split die 13 is vertically movable within the mold mounting hole 14, and a compression coil spring 18 serving as an elastic support means connects the spring receiving groove 15a and the locking hole 14a recessed in the lower end surface of the mold mounting hole 14. installed between
The divided die 13 is elastically supported by a compression coil spring 18, and elastically urged upward by the spring 18.

Further, a notch 16a formed in the left half of the upper end of the guide portion 16 is disposed in the front-rear direction, and a stopper 16a is fixed to the die 4 at both ends thereof.
9, the split die 13 is held against the stopper 1.
9 restricts movement of the die 4 upward from the upper surface.

The horizontal mold 12 has a substantially L-shape when viewed from the front, and its horizontal die forming portion 20 is slidably inserted into the guide hole 17 . The width of the punch hole 10 in the front and back direction is equal to the length of one side of the punch hole 10 in the front and back direction.

A T-shaped groove 21a is formed in the center in the front-rear direction of the vertical arm 21 of the horizontal mold 12, extending from a slightly upper part of the middle stage of the arm 21 to the upper end of the arm 21,
A T-shaped metal fitting 24 attached to the tip of the piston rod 23 of the air cylinder 11 is engaged in the T-shaped groove 21a so as to be movable up and down.

The air cylinder 11 is driven by receiving compressed air from a compressed air supply device (not shown), and the horizontal type 12 is connected to the right end surface of the arm portion 21 and the guide portion 16.
As shown in FIGS. 1 and 2, there is a molding position in which the right end of the die forming part 20 protrudes into the molding cavity 31 by a predetermined length by contacting the left end surface of the arm part 2.
The left end surface of 1 and the left end surface of the mold mounting hole 14 are in contact with each other,
The die forming section 20 is driven to a retracted position where the right end surface of the die forming section 20 coincides with the right end surface of the guide section 16 forming the left side surface of the molding cavity 31 .

When the horizontal mold 12 is in the molding position, the undercut portion 30 of the powder compact 29 is formed by the portion of the die forming portion 20 that protrudes into the molding cavity 31.
is formed.

The lower punch 5 has a square shape in a plan view and is vertically slidably disposed in the punch hole 10 of the die 4, and has a guide portion 25 larger than the lower punch 5 at its lower end.
is formed.

An air cylinder 6 for driving the lower punch 5 in the vertical direction is mounted and fixed on the base 2, and the upper end of the piston 26 is fixed to the guide part 25 of the lower punch 5. Four guide rods 27 extending from the guide rod 27 are inserted through the guide portion 25, and a locking portion 27a is formed at the upper end of each guide rod 27.

Then, the air cylinder 6 is driven by receiving compressed air from a compressed air supply device (not shown),
As shown in FIG. 1, the lower punch 5 has a powder primary filling position where the upper end of the guide part 25 and the locking part 27a of the guide rod 27 are in contact with each other, and a lower end of the guide part 25 is in the upper end of the cylinder body 32 of the air cylinder 6. It is driven to the abutting powder secondary filling position and press position.

A hydraulic cylinder (not shown) that drives the Atsupah punch 9 is incorporated in the upper frame 8,
The hydraulic cylinder is driven by the hydraulic pressure supplied from the hydraulic supply source, and the atsuppa punch 9 attached to the tip of the ram 28 moves between a press position for molding the powder compact 29 and a retracted position shown in FIG. driven.

In the above configuration, the operation when molding a powder compact will be explained with reference to FIGS. 5 to 7.

As shown in FIG. 5, the air cylinder 11 is driven to move the horizontal mold 12 to the retracted position, the air cylinder 6 is driven to move the lower punch 5 to the powder primary filling position, and the underside of the powder compact 29 is moved. Primary cavity 3 corresponding to the lower part of the cut portion 30
1a is formed, and powder is filled into the primary cavity 31a.

Next, as shown in FIG. 6, the air cylinder 6 is driven to lower the lower punch 5 to the press position, and the air cylinder 11 is driven to move the horizontal mold 12 to the molding position.

At this time, the tip of the die forming portion 20 of the horizontal die 12 protrudes into the secondary cavity 31b.

In this state, the powder enters the secondary cavity 31.
filled in b.

Next, as shown in FIG. 7, the upper punch 9 is lowered by driving the hydraulic cylinder of the upper frame 8 to start pressing the powder.

As the powder is pressed, the downward pressing force of the punch 9 becomes greater than the upward elastic biasing force of the compression coil spring 18, and the dividing die 13 and horizontal die 12 are moved downward as the powder contracts. .

In the above case, in the T-shaped groove 21a of the horizontal mold 12, the T-shaped fitting 24 of the air cylinder 11 is connected to the T-shaped groove 21a.
It will slide upward within 1a.

The upper punch 9 descends to the pressing position, and when the pressing is completed, the upper punch 9 is moved to the retracted position, the horizontal mold 12 is moved to the retracted position, the lower punch 5 is raised to the powder primary filling position, and the powder compact 29 is moved to the retracted position. is taken out.

Powder compact 29A (pulley, etc.) illustrated in FIG. 9
When manufacturing, the mold mounting hole 14, the split die 1
3. One pair each of the horizontal mold 12, air cylinder 11, compression coil spring 18, etc. are provided at symmetrical positions with respect to the punch hole 10, and one pair is obtained by dividing the ring-shaped undercut portion of the powder compact 29A in half. It will be horizontal type for each.

Incidentally, instead of the compression coil spring 18, an air cylinder or the like may be used to elastically support the divided die 13 and elastically bias it upward.

As described above, by providing the horizontal die 12 on the split die 13 and driving the air cylinder 11, the undercut portion is formed at the tip of the horizontal die 12, so the number of molding steps for producing the powder compact 29 does not need to be increased. , it is possible to produce a powder compact having an undercut portion and having a high compaction density.

[Brief explanation of the drawing]

The drawings show an embodiment of the present invention, and FIG. 1 is a longitudinal sectional front view of the main part of a powder press molding device, FIG. 2 is an enlarged view of the main part of FIG. 1 (FIG. 3 - line sectional view), The figures are a cross-sectional view taken along the line shown in FIG. 2, FIG. 4 is a cross-sectional view taken taken along the line taken from FIG. 3, FIG. Fig. 7 is an explanatory drawing illustrating the state in which the tip of the powder is protruded into the molding cavity for secondary filling with powder, Fig. 7 is an explanatory drawing illustrating the state in which the powder is pressed by an Atsupah punch, and Fig. 8 is The perspective view and FIG. 9 are longitudinal cross-sectional views of a powder compact according to a modified example. 1...Powder press molding device, 4...Die, 9...
...Atsupa Punch, 11...Air Cylinder, 12...
...Horizontal (side core), 13...Divided die, 14
...Mold mounting hole, 18...Compression coil spring, 20...
...Die forming part, 21... Arm part, 29, 29A...
Powder compact, 30... Undercut portion, 31...
...molded cavity.

Claims (1)

[Scope of Claim for Utility Model Registration] In a powder press molding device for press molding powder to produce a powder compact having an undercut portion on the side surface, a vertically movable split die is provided in the die portion forming the side portion of the molding cavity. a side core is provided in the split die so as to be horizontally slidable, and an actuator is provided for driving the side core to a molding position where the inner end thereof protrudes into the molding cavity and a retracted position where the inner end thereof retracts from the molding cavity; A powder press molding apparatus characterized in that an elastic support means is provided which elastically supports the divided die and allows the divided die to be lowered by the pressing force when the powder filled in the molding cavity is pressed with an atspa punch.